At present, bicycle is not just a means of transportation but a tool for exercise, leisure, entertainment, tourism purpose, and it tends to be developed further as fitness equipment.
Compared with the traditional single-drive bicycle only powered by human legs, a dual-drive bicycle that requires the rider to use both hands and feet has obvious advantages mainly in that it greatly improves drive efficiency and exercises the rider's upper limb. At present, this dual-drive design is mainly applied in traditional upright bicycle with saddle. For example, in a Chinese patent literature titled “Bicycle Front Wheel Drive” (Publication Patent Number: CN2818318Y), a crank sprocket is used for driving the front wheel; in a Chinese patent literature titled “Combined-Drive Bicycle” (Publication Patent Number: CN102498034A, a crank rotary bevel gear is used for drive and for power transmission to the rear wheel; in another Chinese patent literature titled “Hand and Foot Driven Bicycle” (Publication Patent Number: CN102180223A), a swing rocker is used for drive and for power transmission to the rear wheel.
Though the above dual-drive methods have improved drive efficiency, defects of upright bicycles with saddle in terms of aerodynamics, human anthropotomy, human biology, hemodynamics and ergonomics remain unsolved: 1. As the rider rides upright on the saddle, the large windward area and air resistance will lower riding efficiency and speed; 2. Upright riding position increases strain on the rider's spine; 3. To eliminate air resistance, the rider has to bend his/her upper body on the steering handle, causing high strain on both abdomen and spin; 4. This position is unfavorable for venous blood backflow of lower limbs; 5. The rider's weight and friction with the saddle make his/her hip uncomfortable and susceptible to other injuries.
To tackle the above disadvantages of traditional upright bicycles with saddle, prone bicycles have been proposed, for example, CN1126683C “Bicycle with Chain Drive, Multi-Gear and Pedal outside the Rear Wheel”; CN2564461Y “Prone Bicycle”; U.S. Pat. No. 5,887,882 “Prone Bicycle” and U.S. Pat. No. 6,050,584 “Bicycle Placing Rider in Substantially Semi-Prone Riding Position”. In the above proposals, rider's body posture has been changed from upright to prone or semi-prone posture. However, rider's body support problem remains unsolved.
A direct combination of existing prone or semi-prone riding structure with dual-drive structure will cause defects like unbalance, uncoordinated movement. In addition, it is not easy for the rider to master riding skills. To further popularize the dual-drive bicycle, it is necessary to improve its drive method and riding comfort and to make its riding skills easier to master.